Structural metal bar.



" No. 832,711. PATENTED 001*. 9, 1906.

7 c. WEBER. STRUCTURAL METAL BAR.

APPLICATION FILED SEPT. 1, 1905.

Mew/2607" 62rd wzer,

4 .7. a W a i'zessaap- UNITED STATES PATENT orruon CARL WEBER, OF CHICAGO, ILLINOIS.

STRUCTURAL METAL BAR.

- of the United States, residing at Chicago, in

the county of Cook and State of Illinois, have invented a new and useful Improvement in Structural Metal Bars, of which the following is a specification.

My invention relates to an improvement in the class of metalbars employed as the reinforcin medium in reinforced concrete struc tures y embedding them in the concrete in the procedure of erecting such structures for the primary purpose of rendering the con: crete elastic by combining its high compressive strength with the high tensile strength of the steel.

In structures of the kind referred to it is the recognized principlethat the two materials employed-namely, steel and concrete which expand and contract correspondingly, or approximately so, under the influence of temperature, form at their contacting surfaces an intimate union of a chemical, as Well as a mechanical, nature, whereby a strong cohesion of the materials ensues and the steel is protected against oxidation. Under the tension strains to which the structure is subjected its safety depends in a large measure upon the extent of cohesive bonding of the two materials, so that it is an object to provide on the metal bars the greatest possible surface area for resentation to the concrete. The ordinary T- ar hitherto most commonly employed, while it 'ves satisfactor results in the direction re erred to, is di cult to place properly in positioning it, especially in eavy girder construction where exact location of the reinforcing members is of primary importance, and, besides, it is difiicult without special bending-machines for the purpose, which, moreover, are rarely at hand where a structure is being erected to bend properly a T-bar, since owing to its unsymmetric crosssection the neutral axis changes whenever the slightest twist in the bar occurs, and this requires a larger factor of safety to be considered in the construction than would otherwise be necessary. My improvement over comes these difficulties by affording a bar having a symmetric cross-section, and yet resenting to the concrete the greatest possile surface area. I

Referring to the accompanying drawings, Figure 1 is a view in perspective of my improved bar, and Fig. 2 a section taken at the Specification of Letters Patent.

Application filed September 1.1905. Serial No. 276,707.

Patented Oct. 9, 1906.

line 2 on Fig. 1 and viewed in the direction of the arrow.

A is my improved steel bar for embedment in the concrete in metal-reinforced concrete structures, comprising a central longltudinal body portion a and four wings a, radiatlng from it preferably at right angles to each other, thus forming between adjacent wings the longitudinal transversely-curved grooves (L The area of the cross-section of the central body portion of the bar is greater than the cross-sectional area of at least any two of the wings, thus insuring great tensile strength in the structure of WhlCh it becomes a art. At intervals along the bar sections 0 the metal of two oppositely-positioned wings are upset, thus thickenin those wing-sections and forming at interva s therein longitudinal recesses b, which are beveled at their ends and widened at their bases, as shown, the metal in the upsetting operation spreading beyond the edges of the wings and forming shoulders I).

By providing the bar with a thickened centralbody portion and four radiating wings, as described, great tensile strength is insured in the concrete structure of which it becomes a part, and large-surfaces are provided on the bar for contact with the concrete, and still greater surface area is presented for contact with the concrete by the recesses and shoulders of the wings, which materially augment the surface area for presentation to the concrete and form depressions by which additionally secure interlockin of the mass of concrete and the bar embe ded therein is afforded.

What I claim as new, and desire to secure by Letters Patent, is

As a new article of manufacture, a reinforcing-bar for metal-concrete construction, consisting of a metal bar having longitudinal wings with the spaces between adjacent wings concavely curved in cross-section, and

longitudinal recesses at intervals in opposite wings having their bases expanded laterally and forming abrupt end shoulders projecting beyond the adjacent surfaces of the unreces'sed portions of the wings inwhich said recesses are formed.

CARL WEBER.

In presence of g A. U. THORIEN, J. H. LANDES. 

